Fix an exception during local ubuntu builds of intrisic generator

This change is to fix the following exception for python 3.9+:
module 'importlib' has no attribute 'util'.

IGC/GenISAIntrinsics/generator/Intrinsic_definition_translation.py

@@ -10,7 +10,7 @@
 import sys
 import re
 import json
-import importlib
+import importlib.util
 import argparse
 from Intrinsic_definition_objects import *
 from Intrinsic_utils import file_path, Path